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Volatile organic compounds (short: VOC and/or VOCs volatile organic compound[s ]) is the collective term for organic, thus carbon-containing materials, which evaporate easily (are volatile) are already present and/or as gas at low temperatures (e.g. ambient temperature). The word volatilely implies the fact that the materials ranking among the group of the VOC evaporate due to their high steam pressure and/or low boiling point fast (evaporates). Volatile organic compounds are divided in accordance with the WHO according to their boiling point and/or the evaporability resulting from it: Table 1: Organization of VOC

However there is no uniform definition, which a VOC is actual. Some definitions actually contain data to the steam pressure, other, usually newer definitions, define VOC over their photochemical reactivity as if sucked. Forerunner substances for the formation of near-surface ozone. Beyond that in some definitions determined organic materials are excluded explicitly from the VOC definition. Explicitly to be excluded in Australia: Carbon dioxide, Carbon monoxide, Kohlensaeure, Carbonate, Metallcarbide, Methan. In Europe: Each organic compound, which results from human activity, with exception of methane, which can produce photochemical Oxidantien by reaction with nitrogen oxides in presence of sunlight. Organic compound with an initial boiling point of at the most 250°C with a standard pressure of 101,3 kPa. All organic compounds anthropogenen or biogenous origin with exception of methane, which can produce photochemical Oxidantien by reaction with nitrogen oxides in presence of sunlight. In the USA: Each chemical compound on the basis excluded from carbon, Carbon monoxide, Kohlendioxid, Kohlensaeure, Metallcarbide or carbonates as well as ammonium carbonate, which are involved in photochemical reactions in the atmosphere Accordingly data are actually assessable to the emission of VOCs only if additionally to the indication also the used definition is called. VOCs are emitted by a multiplicity of anthropogener and biogenous processes into the environment. Plants, animals, soils and seas are natural sources; the industrielle application of solvents and traffic belong to the most important anthropogenen sources. Natural sources All organisms (humans, animals, plants, Mikroorganismem) emit organic compounds into the environment. Thus e.g. sumps represent enormous sources of methane. Many plants emit terpene and other organic materials. Anthropogene sources During the release of volatile organic compounds, caused by humans, dominate the use of solvents and the traffic. If one regards the methane mission from the cultivation of rice as anthropogene source for VOCs, then a significant source results here likewise. Beside the VOCs in the atmosphere volatile organic materials are also in interior air. Sources for this VOC are among other things. Building materials, furniture and carpets, cleaning agents, as well as the consumption of tobacco products.